Salts and amides of trans-delta**22-5beta-taurocholenic acid and method for the preparation thereof

ABSTRACT

A METHOD FOR THE PREPARATION OF THE SALTS AND AMIDES OF TRANS-$22-5B-TAUROCHOLENIC ACID WHICH COMPRISES TREATING THE CORRESPONDING SALT OR AMIDE OF 5B-23-HALOTAURO CHOLANIC ACID WITH A REGENT CAPABLE OF ELIMINATING HYDROGEN HALIDE. THE PRODUCTS ARE HYPOCHOLESTEROLEMICS AND HYPOLIPEMICS WHICH HAVE UTILITY IN THE TREATMENT OF CONDITIONS ASSOCIATED WITH BLOOD LIPID DEPOSITION.

United States Patent 3,634,465 SALTS AND AMIDES OF TRANS-A -S/S-TAURO-CHOLENIC ACID AND METHOD FOR THE PREPARATION THEREOF Victor J. Grenda,Warren, N.J., assignor t0 Merck & Co., Inc., Rahway, NJ. No Drawing.Filed May 16, 1969, Ser. No. 825,413 Int. Cl. C07c 169/64 US. .Cl.260-397.1 6 Claims ABSTRACT OF THE DISCLOSURE A method for thepreparation of the salts and amides of trans-A -fi-taurocholenic acidwhich comprises treating the corresponding salt or amide of5/3-23-halotaurocholanic acid with a reagent capable of eliminatinghydrogen halide. The products are hypocholesterolemics and hypolipemicswhich have utility in the treatment of conditions associated with bloodlipid deposition.

This invention relates to a novel method for the preparation of saltsand amides of trans-A -5 8-taurocholenic acid via the reaction of a5,8-23-halotaurocholanic acid amide or salt derivative thereof with areagent capable of eliminating hydrogen halide.

The products of the instant process are pharmacologically activeproducts which effectively reduce the concentration of cholesterol,triglycerides and other lipids in blood serum and, therefore, ameliorateconditions associated with blood lipid deposition.

In accordance with this invention the salts and amides of trans-A-5fl-taurocholenic acid (I, infra) are obtained by treating aSfi-23-halotaurocholanic acid salt or amide thereof (II, infra) with areagent capable of eliminating hydrogen halide, for example, inorganicbases including alkali metal or alkaline earth metal bases such ascalcium carbonate, sodium carbonate, potassium carbonate, lithiumcarbonate and the like in the presence of an alkali metal halide such assodium bromide, potassium iodide, lithium bromide and the like or withan alkali metal alkoxide such as potassium tert-butoxide and the like oran organic base, for example, a tertiary amine such asN,N-dimethylaniline, quinoline and the like, an organic acid, forexample, a lower alkanoic acid such as formic acid and the like. Theprocess may be conducted in any solvent in which the reactants arereasonably soluble and which is substantially inert to the reagentsemployed. Suitable solvents include, for example, N,N-dimethylformamide, N,N-dimethylacetamide, tertiary butanol, N-methylpyrrolidone andthe like. The temperature at which the reaction is conducted is not aparticularly critical aspect of this invention but, in general, it ismost convenient to conduct the reaction at the reflux temperature of thesolvent employed. The following equation illustrates this method ofpreparation:

Patented Jan. 11, 1972 SOzR wherein X is halo, such as bromo, chloro andthe like; R is OM wherein M is a cation derived from an alkali metalsuch as potassium, sodium and the like; an amino radical or a derivativeof an amino radical having the formula: NR R wherein R and R are thesame or different members selected from hydrogen or lower alkyl such asmethyl and the like.

A preferred embodiment of this invention relates to the alkali metalsalts of trans-A -5fl-taurocholenic acid which are prepared by treatinga 5,8-23-halotaurocholanic acid alkali metal salt with a reagent capableof eliminating hydrogen halide. The following equation illustrates thisprocess:

0 II S 0 M (ll h wherein X is halo and M is a cation derived from analkali metal.

The 55-23-halotaurocholanic acid salts and amides (II, infra) which areemployed as starting materials in the preparation of the salts andamides of trans-A -5fi-taur0- cholenic acid (I, supra) are obtained bytreating a 5fi-23- halocholanoyl halide (III, infra) with an aqueoussolution of taurine, a taurine salt or a taurine amide while maintainingthe pH of the reaction mixture at from about 7 to about 9. Bases tomaintain the reaction mixture at the desired pH include, for example,alkali metal bases such as potassium hydroxide, sodium hydroxide,potassium carbonate, sodium carbonate, potassium bicarbonate, sodiumbicarbonate and the like. The temperature at which the reaction isconducted is initially from about 30 C. to about 5 C. which, afterseveral hours, may thenbe elevated to the boiling point of theparticular solvent employed. The solvents employed are preferably watermiscible solvents such as tetrahydrofuran, dioxane, dimethylformamide,1,2-dimeth0xyethane and the like although water immiscible solvents suchas chlorobenzene, toluene, ethyl acetate and the like may also beemployed. The following equation illustrates this method of preparation:

O NNNS 02R wherein R and X are as defined above, X is halo such aschloro and the like and R is hydrogen or R wherein R is as definedabove.

The fl-23-halocholanoyl halide (HI, infra) which is the precursoremployed in the preparation of the salts and amides of5,9-23-halotaurocholanic acid (II, supra) is conveniently prepared bytreating 5/3-cholanic acid (IV, infra) with a halogenating agent, forexample, a thionyl halide such as thionyl chloride and the like toafford a SB-cholanoyl halide (IVa, infra) which intermediate is thentreated with a second reagent capable of substituting halogen forhydrogen at the carbon atom alpha to the carbonyl carbon as, forexample, with molecular halogen such as bromine and the like or with asulfuryl halide such as sulfuryl chloride and the like to yield thedesired 5;?- 23-halocholanoyl halide. The reaction is convenientlyconducted in the presence of excess thionyl halide and at the refluxtemperature of the particular thionyl halide employed. The followingequation illustrates this process:

ll C-OH ll/ l l x2 or SOzXz wherein X and X are defined above, X ismolecular halogen such as bromine and the like, SOX is thionyl halidesuch as thionyl chloride and the like and SO X is sulfuryl halide suchas sulfuryl chloride and the like.

There is no clear agreement about the actual role of cholesterol andtriglyceride synthesis in the localization of atherosclerotic plaquesbut numerous studies support the concept that cholesterol andtriglyceride play a major role in the pathogenesis of atherosclerosisbecause along with other lipids and fibrin they accumulate in thearterial intima and subintima to produce arterial corrosion.

Cholesterol and triglycerides are present to some extent in all ordinarydiets and, also, they are synthesized by body organs from intermediatesof metabolic origin; consequently, the development of a chemotherapeuticagent which will induce a significant reduction in the serum cholesteroland triglyceride level is considered desirable. The A -5fl-taurocholenicacid salts of this invention have been tested and found to exhibit goodhypocholesterolemic and hypolipemic activity. The ability of theproducts to inhibit and reduce the concentration of cholesterol andother liquids in serum bespeaks their usefulness as pharmacologicallyactive compounds which have application in the treatmentof conditionsassociated with cardiovascular disease. a

The examples which follow illustrate the method for preparing the A-5fl-taurocholenic acid salts and amides of this invention. However, theexamples are illustrative only and it will be apparent to those havingordinary skill in the art that all of the instant products may beprepared in an analogous manner by substituting the appropriate startingmaterials for those set forth in the examples.

EXAMPLE 1 Trans-A -Sfi-taurOcholenic acid potassium salt Step A:5B-23-bromocholanoyl chloride-A solution of Sfl-cholanic acid (15.5 g.,43 m. moles) in thionyl chloride (60 ml.), at reflux, is treated withbromine (2.8 g.). Reflux is continued for 12 hours after which theexcess thionyl chloride and bromine is removed under vacuum to yield5fl-23-bromocholanoyl chloride.

Step B: Potassium 53-23-bromotaurocholante-The 5fl-23-bromocholanoylchloride is dissolved in tetrahydrofuran (300 ml.) and the mixturecooled to 20 C. An ice cold solution of taurine (5.66 g., 45.2 m. moles)in water (10 ml.) containing milliequivalents of potassium. hydroxide isadded slowly (about 45 minutes) in order to keep the pH of the solutionabout 9. The reaction is aged at 20 C. for 3 hours then heated at 60=65C. for 2 hours. The reaction mixture is concentrated under vacuum toafford potassium 55-23-bromotaurocholanate.

Step C: Trans-A -5B-taurocholenic acid potassium salt-Potassium513-23-bromotaurocholanate (29.4 g.) is suspended in dimethylformamide(200 ml.). Calcium carbonate (8 g.) and potassium bromide (8 g.) areadded and the resulting mixture is then refluxed for 5 hours. Water (40ml.) is added to the hot reaction mixture to dissolve the product andthe inorganic material is removed by filtration. Trans-ASfi-taurocholenic acid potassium salt crystallizes upon cooling thedimethylformamide water solution to 0-5 C. and the product is thencollected on a funnel, washed with two 35 ml. portions of water anddried at C. to yield trans-A -5fi-taurocholenic acid potassium salt.

Elemental analysis for C H NSO' K.--Calcd. (percent): C, 51.98; H, 8.40;N, 2.78; S, 6.34. Found (percent): C, 62.20; H, 8.43; N, 2.92; S, 6.56.

EXAMPLE 2 Trans-A 5,8-taurocholenic acid potassium salt Step A:5B-23-chlorocholanoyl chloride-To a refluxing solution of Sfi-cholanicacid (25 g.) in thionyl chloride (100 ml.) there is added sulfurylchloride (28 ml.) over a one-hour period. Refluxing is continued for 20hours after which the excess reagents are removed under vacuum to yield5,8-23-chl0rocholanoyl chloride.

Step B: Potassium 55-23chlorotaurocholanate.Thc 5 ,6-23-chlorocholanoylchloride obtained according to Step A is dissolved in tetrahydrofuran(500 ml.) and cooled to -25 C. The solution is treated with an ice coldmixture of taurine (9 g., 72 m. moles) in water (18 ml.) containing 144milliequivalents of potassium hydroxide over 65 minutes in order to keepthe pH below 9.5. The reaction is aged at 20 C. for 3 hours and then atroom temperature for 5 hours, after which the solvents are removed byvacuum distillation. The crude potassium 5/3-23- chlorotaurocholanatethus obtained is used directly in the next step.

Step C: Trans-A -SB-taurocholenic acid potassium salt. -The potassium 58-23chlorotaurocholanate obtained according to Step B is suspended intert-butanol (500 ml.) and treated with potassium tert-butoxide (10.0g.). The reaction mixture is refluxed for 10 hours and then cooled to -5C. and the product collected by filtration. Inorganic material isremoved by washing with three 150 ml. portions of water to yield, afterdrying at 100 C. under vacuum, anhydrous trans-A 3-taurocholenic acidpotassium salt.

EXAMPLE 3 Trans-A -5/3-taurocholenic acid sodium salt Step A:Sodium-5fl-23-bromotaurocholanate.-By substituting for the potassiumhydroxide recited in Example 1, Step B, an equimolar amount of sodiumhydroxide and by following substantially the procedure describedtherein, there is obtained sodium-5 8-23-bromotaurocholanate.

Ste B: Trans-A 5/8-taurocholenic acid sodium salt. By substituting forthe potassium 5,8-23-bromotaurocholanate, calcium carbonate andpotassium bromide of Example 1, Step C, an equimolar quantity ofsodium-5,8-23- bromotaurochlolanate, sodium carbonate and sodiumbromide, respectively, and by following substantially the proceduredescribed therein, there is thus obtained trans-A SB-taurocholenic acidsodium salt.

Elemental analysis for C H NSO4Na.Calcd. (percent): C, 64.03; H, 8.68;N, 4.72. Found (percent): C, 64.28; H, 8.80; N, 4.53.

EXAMPLE 4 Trans-A 5 ,B-cholenic acid taurine amide Step A:5/3-23-chlorocholanic acid taurine amide.To a solution of5p-23-chlorocholanoyl chloride in tetrahyrofuran (500 ml.) at 25 C isadded an ice cold mixture of taurine amide (72 m. moles) in Water (18ml.) containing 72 milliequivalents of potassium hydroxide at such arate "as to maintain the pH of the reaction mixture below 9.5. Thereaction mixture is maintained at 20 C. for 3 hours and then at roomtemperature for 5 hours. Removal of the solvent, under vacuum, yields5,8-23-chlorocholanic acid taurine amide.

Step B: Trans-A -5fl-cholenic acid taurine amide.-A suspension of5fi-23-chlorocholanic acid taurine amide in dimethylformamide (200 ml.)is treated with calcium carbonate (8 g.) and potassium bromide (8 g.).The mixture is refluxed for 5 hours. The solvent is removed under vacuumand the residue dissolved in chloroform. The solution is washed withwater, dried over magnesium sulfate, filtered and evaporated undervacuum to yield crude trans- A -55-ch0lenic acid taurine amide. Theproduct is then dissolved in tetrahydrofuran, filtered and petroleumether is added to precipitate pure trans-A -5fi-cholenie acid taurineamide.

Elemental analysis for C H N SO .Calcd. (percent) C, 66.96; H, 9.68; N,5.94. Found (percent): C, 67.20; H, 9.55; N, 6.03.

By substituting for the taurine amide of Step A, Example 4, an equimolarquantity of taurine dimethyl amide and by following substantially theprocedure described therein,

there is obtained 5B-23-chlorocholanic acid taurine dimethyl amidewhich, when substituted for the 55-23- chlorochola-nic acid taurineamide of Step B, Example 4, and following substantially the proceduredescribed therein, aflords trans-A -5fi-cholenic acid taurine dimethylamide.

EXAMPLE 5 Trans-A SB-taurocholenic acid potassium salt Step A: Potassium5/3-23-bromotaurocholanate.-To a solution of 5fl-23-bromocholanoylchloride (43 m. moles) in tetrahydrofuran (300 ml.) at 20 C. is slowlyadded a solution of taurine potassium salt (45 m. moles) in water (10ml.). The pH of the solution is maintained between 7 and 9 by theaddition of a solution of potassium hydroxide (45 m. moles) in water (10ml.). The reaction mixture is aged at 20 C. for 3 hours and thenrefluxed for 2 hours. The solvent is removed under vacuum to yieldpotassium 5fi-23bromotaurocholanate.

Step B: Trans-A -5fi-taurocholenic acid potassium salt. 'By substitutingpotassium 55-23bromotaurocholanate for the potassium513-23bromotaurochola-nate, calcium carbonate and potassium bromiderecited in Example 1, Step C, and following the procedure describedtherein, there is thus obtained trans-A -5fl-taurocholenic acidpotassium salt.

The above examples are merely illustrative of the instant method and itis to be understood that this invention is not to be limited by thespecific examples but rather,

embraces all variations and modifications thereof which fall within thescope of the foregoing discussion and the appended claims.

I claim:

1. A compound having the formula:

wherein R is halo, -NHCH CH SO OM wherein M is a cation derived from analkali metal or wherein R and R are the same or different membersselected from hydrogen or lower alkyl and X is halo.

2. A compound according to claim 1 having the formula:

\AI/KNQV Ar X wherein M is the cation derived from an alkali metal and Xis halo.

3. A compound according to claim 2 wherein the alkali metal cation isselected from potassium or sodium.

7 4. A process for preparing a compound having the formula:

vvkgv wherein X is halo and R is --OM wherein M is a cation derived froman alkali metal or NR R wherein R and R are the same or differentmembers selected from hydrogen or lower alkyl; which comprises treatinga compound having the formula:

wherein X is as defined above and X is halo, with a reagent having theformula: H NCH CH SO R, wherein R is as defined above, in the presenceof a base.

5. A process according to claim 4 for preparing a compound having theformula:

wherein X is halo and M is potassium or sodium; which comprises treatinga compouund of the formula:

wherein X is halo with a compound having the formula: H NCH CH SO M,wherein M is as defined above, in the presence of a base.

6. A process for preparing a compound having the formula:

wherein X and X are halo; which comprises treating 5;?- 3r cholanic acidwith a reagent capable of forming an acyl halide to afford a compoundhaving the formula:

wherein X is as defined above, followed by the treatment of saidcompound with a halogenating agent.

References Cited UNITED STATES PATENTS 3,463,795 8/1969 Sarel et al.260-3971 ELBERT L. ROBERTS, Primary Examiner

